Thomas lalob



i Unire@ Sterns karnNr @einen THOMAS LALOR, OF TORONTO, ONTARIO, CANADA, ASSIGN OF ONE-HALF TO WILLIAM HAMILTON, OF SAME PLAGE.

LATCH.

SPECIFICATION forming part of Letters Patent No. 257,725, dated May 9, 1882. Application filed August 29, 1881. (Model.)

To all whom it may ccnccra:

Be it known that I, THOMAS LALoR, ofthe city ot' Toronto, in the county of York, in the Province of Ontario, Canada, have invented certainnew and useful Improvements in Locks, of which the following is a. specification.

The object of the invention is to produoe'a simply-constructed and strong lock specially designed for prisons, and which cannot easily be strained or otherwise put outot' order; and it consists essentially of a cylindrical block pivoted within a lock-frame andhavingavertical slot cutin it to receive the bar of the gate it is intended to secure, the said lock being so connected to the latching and locking mechanism that no strain can be exerted through it to the said mechanism, as hereinafter more particularly explained.

In the drawings,Figure l is a portion of a prison-wall with'my improved rotary lock set in position and exhibiting the gate or door locked. Fig. 2 is a perspective View of the lock with a portion of the frame removed and exhibiting the position of the cylindrical block and tumblers when the block is set to receive the bar. Fig. 3 is a similar view of the lock, showing the cylindrical block in the position it will appear when the gate is closed and latched. Fig. tis a similar view, showing the position of the tumblers when the'block is locked.

In the drawings, A represents a portion of a stone wall forming a jamb of the door leading into a cell.

B is the door or gate of the cell.

Gis a cylindrical block, provided with a spindle, D, and pivoted within the frame E. The

spiral sprin g F is arranged to hold the block in the position shown in Fig. 2 when not otherwise acted upon.

Gr is a notch out in the block C, sufficiently large to receive the end bar of the door or gate B, or a bar attached thereto.

H is a wing or projection attached to or forming part of the cylindrical block.

I is a tumbler operated by the key, and having a foot arranged to lit between the wingH and frame of the lock when the cylindrical -block has been changed from the position shown in Fig. 2 to the position it is exhibited 5o in Fig. 3, where the lock is shown latched.

J is a tumbler, also operated by the key, and designed to lit over the foot of the tumbler I, in order to hold it down, and thereby lock the lock, as shown in Fig. 4. The other tumblers exhibited in the lock are ot' the ordinary kind, designed to prevent the lock being picked.

K is a semicircular guard-piece, extending from the back of the lock around a portion ot the circumference of the cylindrical block C, 6o

tact with the inner side of the notch, pushing the block around upon the spindle till the notch reaches the position shown in Fig. 3, by which time the wing or projection H willhave been carried from the position shown in Fig.

2 to the position in which it is shown in Fig. 7o I 3, when the latch-tumbler I drops down behind it, thereby holding the block stationary, and securing the end bar of the gate between the notch and guard-piece K, as shown inFi g.

1. IIn order to lasten it in this position doubly secure, the key is turned so that the lookin gtumbler J is thrown forward till it rests upon the foot of the tumbler I, as shown in Fig. 4, preventing the latter tumbler being raised from behind the wing H. In order to open 8o the door, the key is turned in the usual direction, when it first withdraws the tumbler J from the position it is shown in Fig. 4. to the position shown in Fig. 3. The nextmovement 1 of the key raises the tumbler J clear of the wing H, which action releases the cylindrical block C, permitting it to be turned upon its spindle by the tension of the spring F, which causes the notch to change from the posit-ion in which itis shown in Fig. 3 to the position 9o shown in Fig. 2, thereby permitting the gate to be opened.

It will be noticed from the description that there is no connection between the cylindrical block C and the tumblers of the lock, except when the latch is locked, and even then there .can be no injurious strain exerted on the tumblers by any pressure which may be directed against the block C. If the notch be acci- I receive the bar of the gate, and pivoted in the dentally turned into the position shown in Fig. frame of a lock provided with a scmicircular 3 while the gate is open, the strain directed guard-piece, K, in combination with a wing or 15 against the lock by the end bar of the gate v projection, H, attached to or forming part of 5 coming in contact with the latter Will be susthe cylindrical block C, and arranged in contained entirely by the block and its spindle, nection with the tumbler I, substantially as and Will not be communicated to the tuinblers, and for the purpose specied. which are necessarily delicate vas compared with the block. Consequently the durability THOMAS LALOR' 1o of the lock is insured. Witnesses:

' What I claim as my invention is O. W. BALDWIN,

A cylindrical block having a notch, G, to LEWIS TOMLINSON. 

